The objective of this final year of support is to complete the analyses of behavioral and histological data on two groups of macaques with surgical lesions of the primary somatic sensory cortex (SmI). Infants receiving partial (area 3 or areas 1 and 2), or total (areas 3, 1, and 2) lesions at 3-5 weeks of age showed normal size and texture discrimination performance within 1-3 months following surgery. A juvenile group given partial or total lesions of SmI at 18-24 months of age were as severely and permanently impaired as adult-lesioned animals in previous studies. The proposed histological studies are necessary to determine the size and location of the cortical removal relative to cytoarchitectural fields in SmI and to topographic projections of body surfaces. Examination and quantification of thalamic degeneration is proposed as an additional source of verification of the extent, topography and submodality of cortical areas removed. Two additional infants will be given total SmI lesions to determine if the recovery of tactile function found following lesions involving (but not completely removing) all cytoarchitectural areas in SmI can be found after total SmI removals.